There is no explanation for evil. It must be looked upon as a necessary part of the order of the universe. To ignore it is childish, to bewail it senseless.
Evil is a moral entity and not a created one, an eternal and not a perishable entity: it existed before the world; it constituted the monstrous, the execrable being who was also to fashion such a hideous world. It will hence exist after the creatures which people this world.
May the forces of evil become confused on the way to your house.
Evil spelled backward is live.